Derivative Financial Instruments - Notional Value of Derivative Contracts (Detail) - USD ($) $ in Millions	Mar. 31, 2026	Dec. 31, 2025
Derivative [Line Items]
Total	$ 1,685,800	$ 1,405,200
Interest rate contracts
Derivative [Line Items]
Total	222,200	137,300
Swaps, futures and forwards
Derivative [Line Items]
Total	222,200	137,200
Options written
Derivative [Line Items]
Total	0	100
Options purchased
Derivative [Line Items]
Total	0	0
Foreign exchange contracts
Derivative [Line Items]
Total	1,380,300	1,195,200
Swaps, futures and forwards
Derivative [Line Items]
Total	1,264,600	1,113,200
Options written
Derivative [Line Items]
Total	25,400	23,800
Options purchased
Derivative [Line Items]
Total	25,600	23,800
Spot
Derivative [Line Items]
Total	64,700	34,400
Total commodities, equities and precious metals
Derivative [Line Items]
Total	56,900	48,400
Swaps, futures and forwards
Derivative [Line Items]
Total	44,300	35,800
Options written
Derivative [Line Items]
Total	1,600	1,700
Options purchased
Derivative [Line Items]
Total	11,000	10,900
Credit derivatives
Derivative [Line Items]
Total	24,800	22,500
Other Contracts
Derivative [Line Items]
Total	$ 1,600	$ 1,800